\(\dfrac{17x}{99}\)

\begin{aligned}
& \frac{4 x}{9}-\frac{3 x}{11} \\
=& \frac{4 x \times 11}{9 \times 11}-\frac{3 x \times 9}{11 \times 9}\\
\text{C}&\text{ommon denominator 99}\\
=&\frac{44 x}{99}-\frac{27 x}{99} \\
=&\frac{44 x-27 x}{99} \\
=&\frac{17 x}{99}
\end{aligned}